Considering Abortion? :
Abortion Questions Answered
When Can I Get An Abortion
How Early Can I Get An Abortion?
Abortion providers use different guidelines to determine how early abortions can be provided.
Some clinics offer abortion as early as the week of your missed period (four weeks after the last menstrual period — or LMP) as long as a pregnancy test comes back positive.  (Read about how early you can find out you're pregnant.)
Other clinics prefer to wait one or two weeks after your last period (5 or 6 weeks from the LMP) so that the presence of the gestational sac can be confirmed by ultrasound. The gestational sac is a sign of early pregnancy. Seeing the gestational sac in the uterus helps rule out the possibility of an ectopic pregnancy (in which the fertilized egg implants outside the uterus). This is important because an ectopic pregnancy can be a medical emergency for the woman and requires special treatment.
About 61% of abortions are performed before 9 weeks, and 88% of abortions are performed before 12 weeks. 
 Providers and Services http://www.guttmacher.org/pubs/fb_induced_abortion.html
 When Women Have Abortions http://www.guttmacher.org/pubs/fb_induced_abortion.html